The best way to deal with pronunciation is to listen to the audio (if you're not already on the relevant page the audio is here):
http://words.bininjgunwok.org.au/words

The IPA is [ŋaʔdi].

For English speakers there are two issues here— a word that starts with the ng nasal (ŋ) and the glottal stop at the end of the first syllable. To pronounce this nasal sound, put the back of your tongue up against the velum (the soft tissue at the back of the roof of the mouth) and then pull it down.

nga- 'first person singular', I.

-h- the glottal stop that marks present action

-di 'the verb to stand, or to be' (especially for elongate objects/animates standing vertically)

The pronoun prefix nga- means 'I'. You can refresh your knowledge of these prefixes on the blog post at:
http://bininjgunwok.org.au/2012/07/

The verb stem -di like -ni and -yo can also be used in the sense of 'to be'.
-yo 'be lying down'
-ni 'be sitting'
-di 'be standing'

Any of the other prefixes can also be added to these verbs:
ngahdi (or nga-rri, when 'd' has a vowel on either side of it it changes from d>rr. The preceding glottal stop stops this from happening).
kabirrih-di 'they are standing'
karrih-di 'we are standing'

Ngahdi Kunbarlanja.
(e.g. on the phone) I am at Gunbalanya.

A: Nakangila baleh wam?
Where has Nakangila gone?

B: Ngahdi.
I'm here.